Electrical power distribution system for enabling distributed energy generation

ABSTRACT

In the present legacy electrical power generation and distribution system, the power quality delivered to end consumers is being degraded by a number of disruptive technologies and legislative impacts; especially with the rapidly increasing myriad of privately owned and operated domestic and commercial distributed energy generation (DEG) devices connected at any point across a low voltage (LV) distribution network. The present invention bypasses this increasing critical DEG problem by offering a solution comprising an energy processing unit (EPU) that is installed at the electrical power point of use (POU).

CLAIM FOR DOMESTIC PRIORITY

This application claims priority under 35 U.S.C. §119 to the U.S.Provisional Patent Application No. 61/889,543, filed Oct. 11, 2013, U.S.Provisional Patent Application No. 61/896,635, filed Oct. 28, 2013, U.S.Provisional Patent Application No. 61/896,639, filed Oct. 28, 2013, U.S.Provisional Patent Application No. 61/908,763, filed Nov. 26, 2013, U.S.Provisional Patent Application No. 61/913,932, filed Dec. 10, 2013, U.S.Provisional Patent Application No. 61/913,934, filed Dec. 10, 2013, andU.S. Provisional Patent Application No. 61/913,935, filed Dec. 10, 2013,the disclosures of which are incorporated herein by reference in theirentirety.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains material,which is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

FIELD OF THE INVENTION

The present invention generally relates electrical power generation anddistribution. Particularly, the present invention relates to methods andsystems for solving the increasing power quality degradation of thepresent legacy electrical system because of evolving technology andlegislative impacts, such as Distributed Energy Generation (DEG).

BACKGROUND

The present legacy electrical system and power quality being deliveredto users is being degraded by a number of disruptive technology andlegislative impacts, especially with the rapidly increasing myriad ofprivately owned and operated domestic and commercial Distributed EnergyGeneration (DEG) devices connected at any point across a low voltage LVpower distribution network. This increasing degradation in power qualitybeing delivered to the end consumers, especially voltage volatility,current and frequency aberrations, can negatively impact the performanceor even damage electrical equipment, appliances, and electronic devicesconnected to the electrical power system in the user premises, and caneven trip and disrupt wider area LV power distribution network,substation protective equipment, high voltage (HV) transmission grids,and even generators.

Referring to FIG. 1. The legacy alternate current (AC) electrical powersystems which started in the later 1800's had limited transmissioncapabilities due to low voltage components, and over short distances. Soa myriad of separate independent power producers (IPP)'s sprang up witha central generator and supplied power to local areas or local powerislands. Back then, there were a range of voltages and variousfrequencies for each local area or local power island. The loads weresimple which comprised largely incandescent electrical lighting.

Referring to FIG. 2. As electrical technologies advanced, with HVinsulators and switches, transmission voltages were allowed to beincreased hence enabling the delivery of higher electrical power overlonger distances. Voltage levels increased rapidly from Edison's initial220 VDC local grids, to the first AC grids of 2.3 KVAC (1893), risingevery few years to 765 KVAC (late 1960's). With longer transmissiongrids resulted in overlapping power islands, conflicts began in areas ofbusiness, competing technical standards, and finally monopolies emerged.With the increasing use of electrical power, questionable reliability,and growing conflicts in the electrical industry, many countries movedto legislate regulatory controls over their electrical industries.

In the United States, it became critical that the rapidly growingelectrical industry be regulated to create national standards that alsowould allow multiple grid interconnections to create stable powernetworks across the country with the goal of delivering high qualityreliable power to the consumers. The Federal Government in the 1992Congress passed the Energy Power Regulatory legislation at the Federallevel. So FERC (Federal Energy Regulatory Commission) was charged withregulating power quality from the central power utilities, who owned thegenerators, transmission, and distribution networks end to end. Then in1996, in order to increase competition and optimize the cost ofelectrical power, FERC deregulated the electrical industry further andruled that generation, transmission and distribution of electrical powermust be conducted by legally separate entities. This created thecompetitive market for wholesale power available on the transmissiongrids with the generators selling and the distributors purchasingwholesale power from the transmission companies.

Many countries enacted similar deregulated competitive electrical powerstructures in the 1900's. In the United States, after a major North EastBlackout in 1965, the NERC (North American Reliability Council) wascreated to maintain and enforce system standards and power qualityreliability. Then again, after another major Blackout in North East andCanada Aug. 14, 2003, the Federal Government in June 2007 passed eventighter regulatory laws and penalties on the transmission operatorsmandated legally by the NERC working with FERC.

Referring FIG. 3. Reaching the present day, what came with thederegulation legislation was DEG, which was the ability of connectingsmall power generators to the HV transmission grids. With still furthertechnology advances in power generation such as CHP micro-turbines, fuelcell installations, and especially renewable energy sources such asphotovoltaic (PV), solar thermal, and wind, coupled with falling capitalcosts, private owners in domestic and commercial premises have statedpurchasing and installing these small DEG devices.

These small privately owned and operated domestic and commercial DEGdevice installations accelerated with the introduction of then laterupdated and modified Feed in Tariff (FIT) policy over the last fewyears. The FIT mandates transmission operators to pay owners of DEGdevices minimum prices for excess power being generated and added backinto the energy grid. So now with a myriad of privately owned andoperated domestic and commercial DEG devices, connected in increasingnumbers to the local LV distribution networks, it is creating a largeimpact on power quality for not only the end consumers, but theincreasing real possibility of wide area major grid disruptions.Especially with the increasing chances of a transmission grid trip dueto the reduction of spinning reserves with the offloading of the largecentral utilities due to additional power being generated by the growingnumber of installed DEG devices. The resultant voltage, current andfrequency aberrations from these privately owned and operated domesticand commercial DEG devices that are superimposed onto the distributionnetworks and transmission grids increases the possibility of setting offthe system trip protective switch gear, normally adjusted to the tighttolerance and long established legacy electrical power specifications.

Furthermore, because of these increasing voltages on the distributionnetworks, when over the regulated voltage limits the DEG interfacecontrol electronics disables the DEG interface, it does not only shutoff any DEG energy recovery from the DEG installation but alsoeliminates any FIT recovery for the end consumers. Hence the more DEGinterfaces connect along a local distribution network, for example aneighborhood of domestic PV installations, as the distribution networkvoltages increase because of the amount of excess energy being deliveredinto the distribution network by the DEG installations, the more numberof these DEG interfaces will be disabled by the DEG interface controlelectronics, with no energy recovery or FIT for the end consumers.

Power quality is defined under the following specifications, the keyparameters being consistent and stable voltage, harmonics, and frequencyof the electrical power delivered to the user. With the advent of moreand more electronic devices and equipment being connected to theelectrical system which are complex electrical loads, especially withthe increasing power demand being domestic and commercial, rather thanindustrial such as in the United States, these electronic devices, sincethey offer more complex loads to the electrical system, they canintroduce electrical power instability, and these electronic devices aregenerally located in domestic and commercial premises with increasingpower demands from the LV distribution networks, adding to the voltageinstability with changing loads and power factors across thedistribution networks.

When the legacy central generating utilities owned the complete equationof generation, transmission and distribution end to end, they agreed to,and could meet, the legislated tight power quality standards specifiedand enforced by government and regulatory bodies. With the advent ofeven further de-regulation of the electricity industry in manycountries, and expanding FIT, allowing the connection of an increasingmyriad of privately owned and operated domestic and commercial DEGdevices to the LV distribution network and increasing complex loads andchanging power factors, there is an increasing critical degradation ofpower quality especially voltage instability and increased potential oflocal and large area major power disruptions.

Electrical equipment, appliances, electronics, and especially electricalmotors, are all designed to perform optimally at the legislated voltageand frequency tight set legacy standards. Electrical and electronicdevices subjected to these voltage and frequency aberrations, outsidethe set tight legacy tolerances, can malfunction, degrade performance,and even be damaged.

These power quality standards have a long history of regulatorynormalization across each country, and even across the world,particularly with the advent of electrical transmission major gridconnections between countries. Examples of electrical LV distributionmains standards by some countries are as follows, referencing nominalvoltage, voltage tolerance, nominal frequency, and frequency tolerance,for the LV distribution network for domestic and commercial users:

Normal Nominal Voltage Fre- Frequency Regu- Voltage Tolerance quencyTolerance Country latory (VAC RMS) (%) (Hz) (%) USA FERC/ 120 (1φ) ±5 60±1 NERC 240 (1φ) 120/208 (3φ) UK EN50160 230 (1φ/3φ) +10, −6 50 ±1

Many countries have similar nominal LV Distribution POU voltages such as220/230/240 VAC (and trending this higher distribution network voltageto 230 VAC), and lower voltages generally 110/115/120 VAC, withFrequency now standard at 50 Hz or 60 Hz. Generally 50 Hz for the higher220/230/240 VAC voltages, and 60 Hz for the lower 110/115/120 VACvoltages, but either frequency is used in some countries due to theirelectrical power system history. voltage tolerance can be standardizedat ±5%/±6%/+10, −6%/±10%, the maximum tolerance in any country is set at±10%.

Frequency tolerance is normally standardized in many countries to ±1%,some countries have ±2%, which is the maximum frequency toleranceallowed.

Power quality problems are associated with voltage or frequencydeviating outside the specified regulatory set and enforced limits.Voltage magnitude problems can be:

-   -   1) Rapid voltage changes;    -   2) Low frequency voltage change causing flicker;    -   3) Under voltage dips (under −10%);    -   4) Over voltage surges (Over +10%)    -   5) Overvoltage spikes and noise;    -   6) Voltage unbalance in 3-phase system;    -   7) Voltage and current harmonics;    -   8) Power factor (PF)−the phase of the voltage and current being        out of phase due to reactive power imbalance referred to as        power factor (PF=1, V and I in phase, PF=0, V and I−180° out of        phase) can also create not only voltage and current harmonic        problems, but also electrical and electronic equipment, and        especially in electrical motors, wasted power, under        performance, and also possible damage;    -   9) Current imbalance in the 3-phase system, where each phase is        loaded with unequal currents can cause transmission and        distribution equipment problems and degraded power quality; and    -   10) Frequency deviations also can impact performance and        operation of electrical and electronic devices, transformers,        and electrical motors;

Because of these increasing voltages on the distribution networks, whenover the regulated voltage limits the DEG interface control electronicsdisables the DEG interface hence not only shuts off any DEG energyrecovery from the DEG installation but also eliminates any FIT recoveryfor the user. Hence the more DEG interfaces connected, for exampledomestic houses, along a local distribution network, for example aneighborhood of domestic PV installations, as the distribution networkvoltages increase because of the amount of excess energy being deliveredinto the distribution network by the DEG installations, a significantnumber of these DEG interfaces will be disabled by the DEG interfacecontrol electronics, with no energy recovery or FIT for the users.

All of these power quality issues degrade the power quality beingdelivered to users, especially voltage instability across and throughthe LV distribution network at POU, where now, in addition, the myriadof privately owned and operated domestic and commercial DEG devicesbeing connected, excess power generated by these DEG devices is beingloaded back onto the local LV distribution network. Also, theseprivately owned and operated domestic and commercial DEG devices, eventhough they have to meet performance test specifications, IEC 61215 (Ed.2-2005) and IEC 61646 (Ed. 2-2008), they can still set up widely varyingVoltage, Frequency and rapid power fluctuations, on the local LVdistribution network at POU. These domestic and commercial DEG devicesare small PV installations, micro-wind, micro-hydro, CHP micro-turbine,CHP fuel cells, and possibly hybrid automobiles in the future. Also,these problems can also reduce the efficiency of electrical power usagein the electrical and electronic loads at the POU. For exampleelectrical motors waste power when they are driven at a higher voltagethan the electric motor was designed for optimal performance, and alsoexcessive PF, voltage and current unbalance and harmonics can not onlydecrease efficiency but also can damage these sensitive electrical andelectronic loads.

The large renewable industrial PV, solar thermal, wind and hydroinstallation need large physical areas away from population centers, thepower users, hence the large industrial installations need end to end HVTransmission over generally long distances, so these large installationscan be owned and controlled by the utility generator, hence can meet andbe responsible for the Transmission Operator regulated power qualitystandards.

The advantage of the large numbers of small privately owned and operateddomestic and commercial DEG devices, is the power is generated locally,close to the users or POU, through the LV distribution network. But theowners of these privately owned and operated domestic and commercial DEGdevices, purchase, install and operate these DEG devices, but have noresponsibility for the impact on the local LV distribution network powerquality. These legacy local LV distribution networks in most cases werenot initially designed for large number of domestic and commercial DEGdevices to be connected. So there is real and increasing concern by theregulatory bodies, with the increasing penetration of these privatelyowned and operated domestic and commercial DEG devices, not only userpower quality being degraded, but local power instability on the LVdistribution networks. Added to this is the increasing connection ofcomplex loads, changing power factors, and changing loads across thedistribution networks. This results in increasing service disruptionsover even large areas and even HV transmission grids due to voltage,current, or frequency aberrations outside the tight tolerance electricalstandards that can trip voltage, current, or frequency electrical systemsafety and protection devices, causing electrical disruptions andoutages. Also because of these increasing voltages on the distributionnetworks, when over the regulated voltage limits, the DEG interfacecontrol electronics disables the DEG interface; thus not only shuts offany DEG energy recovery from the DEG installation but also eliminatesany FIT recovery for the user.

The electrical power industry and regulatory bodies are grappling withthis new and disruptive evolution in the legacy electrical system.Suggested solutions to this increasing and real problem are all aimed atmaintaining the legacy and historical transmission and distributionnetwork structure and power quality tolerances.

One significant book, which is dedicated solely to the looming problemof increasing penetration of privately owned and operated domestic andcommercial DEG devices is titled “Integration of Distributed Generationin the Power System”, authored by Math Bollen and Fainan Hussan. Thecontent of which is incorporated herein by reference in its entirety.This book was only recently published in 2011 by IEEE, and the bookrepresents a detailed in-depth-study of over a 10 year period, allrelated to the disruptive evolution of privately owned and operateddomestic and commercial DEG devices on power quality.

This book has 470 references, and is excellent in its in-depth researchon detail to the increasing critical aspects of the disruptive impact ofDEG devices on the overall electrical power system. Many authors andinstitutions present similar solutions to solving this problem, the samesolutions as also covered fully in detail in this book, and again allaimed at maintaining the legacy electrical standards power qualitytolerances, by protecting and controlling the HV transmission grid andLV distribution networks. But again, all of these solutions suggestedare solely to maintain these historical, long established over manydecades, of legacy tight tolerance electrical industry standards. Thisdeeply researched and detailed book finally concludes in itsrecommendations to address the critical problems of the increasingconnection of larger numbers of privately owned and operated domesticand commercial DEG devices, is by adding a layer of digitalcommunication networks to link the DEG devices back to controlling andprotecting the HV transmission grids, or even this digital communicationnetwork can precipitate tripping voltage protection relays on thedistribution network feeders, or even disconnecting DEG devices if sayovervoltage results. The book also suggests various schemes of addingstorage, and other load shifting actions based upon the added digitalcommunication network of shifting reserves to customers or DEG devices.

The book also concludes another possible conventional solution becauseof the concerns of the large cost, time, and complexity involved to addthe extensive sophisticated digital communication networks and softwarealgorithms that would be required, so in their final paragraph on page470—“Next to these advanced solutions, the classical solution ofbuilding more stronger lines or cables should not be forgotten. However,the introduction of new types of production will require use of advancedsolutions in more cases than in the past. By combining the classical andadvanced solutions, the power system will not become an unnecessarybarrier to the introduction of distributed generation.”

So this last paragraph of the book on page 470, sums up their concernsof the increasing penetration of privately owned and operated domesticand commercial DEG devices on the LV distribution network in particular,and its potential critical impact on the stability of the overallelectrical grid. They propose advanced digital communication networksand software solutions (“Smart Grid”), but also suggest a simple, butexpensive, conventional physical solution in adding more copper wire tothe existing LV distribution networks that will increase the powerhandling capability and reduce Voltage instability by decreasing theresistance of the wires in the present LV distribution networks as theseDEG devices add increasing and volatile power onto the local LVdistribution networks. These LV distribution networks were initially notdesigned, and certainly this new DEG problem, not anticipated, with thisrecent evolution of the connection of large numbers of privately ownedand operated domestic and commercial DEG devices.

The last paragraph in this detailed book underlines clearly that:

-   -   1) All solutions suggested are aimed and still meeting the        present tight tolerances of the historical legacy Regulated and        enforced electrical standards for power quality;    -   2) Connection of large numbers of privately owned and operated        domestic and commercial DEG devices to the local LV distribution        networks is a major problem, as the LV distribution networks        were not initially designed to handle this new disruptive        electrical evolution, hence the suggestion of physically        upgrading these LV distribution networks underlines the        complexity of this real and critical problem;    -   3) The book's last line suggests, because of the complexity and        cost and time for these advanced complex “digital” solutions        (“Smart Grid”), that just adding additional copper wires to the        present LV distribution network will help. But that is also a        very expensive solution, to upgrade physically the LV        distribution networks, and will take many years to complete;    -   4) With these critical problems now happening with the        degradation of power quality and possible widespread        Transmission grids tripping, there may be legislative moves to        limit the number of privately owned and operated domestic and        commercial DEG devices allowed to be installed;    -   5) The book also has no suggestion on who would be responsible        for the costs of the huge digital communication software network        and who has final responsibility for power quality delivered to        the user; and    -   6) Again, the book, and all suggestions in the industry,        surrounding this recently evolving DEG devices problem, is the        underlying, totally accepted without question, in maintaining        the historical, legacy, Regulated power quality tight        specifications and framework, and still meeting the decades old        legacy electrical system power quality tight tolerance        standards.

SUMMARY

So far, solutions that have been proposed by the industry attempt tosolve this increasing critical problem due to the introduction of DEG bytargeting the power generation, HV transmission, and/or LV distributionwithout real success. The present invention, however, approaches theproblem by targeting directly the electrical power point of use (POU),so that high quality electrical power can be restored directly at eachPOU. As such, the present invention transforms the tightly legislatedand regulated legacy “electrical grid” into a sort of “open-source”energy grid with wide tolerance. In this “open-source” energy grid, anindividual energy processing unity (EPU) device is installed at each endconsumer's POU. These EPU devices are specifically designed to tolerantvery wide ranges of voltage, current, and frequency variation—“dirtypower” on the input, and processes the input “dirty power” to produceclean high quality power at the output delivered directly at the POU.The present invention then enables the LV distribution network inparticular to handle the increasing number of connections of privatelyowned and operated domestic and commercial DEG devices while meeting therequirements of tightly regulated and legislated legacy electricalstandards imposed on HV transmission operators.

The specific definition of point of use (POU) in this document is asingle circuit point of connection between the end consumer and the LVgrid. As such, a EPU can be installed at the end consumer POU, but notlimited to directly at a switchboard in the end consumer's premises,electrical power connection service point, switch room, remotely at asingle circuit connection to a single the end consumer's premises orload, in an adjacent location inside or outside of the end consumer'spremises, or on an electric pole. A person ordinarily skilled in the artwill view that a POU as defined in this document is where an EPU isinstalled, which can be between the end consumer's premises or load andthe LV grid for a point-to-point connection, or any single circuitconnection by a end consumer.

The specific definition of end consumer includes that of a conventionalelectrical power consumer on an energy grid and an owner and/or operatorof a DEG device connected to an energy grid.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are described in more detail hereinafterwith reference to the drawings, in which

FIG. 1 depicts a logical diagram illustrating the electrical powergeneration and distribution networks during the late 1800's;

FIG. 2 depicts a logical diagram illustrating the electrical powergeneration and distribution networks during the 1900's;

FIG. 3 depicts a logical diagram illustrating the present day electricalpower generation and distribution networks with DEG devices but withoutthe present invention;

FIG. 4 depicts a logical diagram illustrating an electrical powergeneration and distribution network with DEG devices and EPU's inaccordance to one embodiment of the present invention; and

FIG. 5 depicts a block diagram illustrating a configuration of en energyprocessing unit in accordance to one embodiment of the presentinvention.

DETAILED DESCRIPTION

In the following description, methods and systems of electrical powergeneration and distribution and the like are set forth as preferredexamples. It will be apparent to those skilled in the art thatmodifications, including additions and/or substitutions may be madewithout departing from the scope and spirit of the invention. Specificdetails may be omitted so as not to obscure the invention; however, thedisclosure is written to enable one skilled in the art to practice theteachings herein without undue experimentation.

With the increasing negative impact to power quality of de-regulationthat allows these privately owned and operated domestic and commercialDEG devices to be connected to the LV distribution networks, especiallywith the further legislation for FIT, and similar allowances in manycountries, this is becoming a critical industry problem that is tryingto be solved in adding complex digital communication networks andcontrol algorithms to the power grids (“Smart Grid”). However, thisapproach is expensive, complex, and will take many years to knit thehuge power system together, and in the meantime it will not improve thepresent situation that allows the connection of an increasing number ofprivately owned and operated domestic and commercial DEG devices to thedistribution networks or solve the increasing addition of complex loads,and changing loads and power factors across the distribution networks.

The major concern expressed by many in the power industry is thestability of the overall power system as the increasing number ofprivately owned and operated domestic and commercial DEG devices areinstalled, that will degrade not only the local LV distributionnetworks, but also can threaten the HV Transmission Grids as morecentral Generating Utilities reduce capacity and spinning reserves dueto the increasing energy being generated and loaded onto the LVdistribution networks from the DEG devices, and the increasing renewableinstallations in general. With reduced central Generator Utilitiesspinning reserves, and more volatile energy being delivered to the LVdistribution networks by the wide array and increasing numbers ofprivately owned and operated domestic and commercial DEG devices, theincreasing chances of Network Voltage and Frequency tripping, and alsothe potential of major outages as HV Grid faults cannot be rapidlycompensated for with insufficient spinning reserves.

One aspect of the present invention is a power distribution system thatcompletely bypasses the critical and increasing problem of the myriadand types of privately owned and operated domestic and commercial DEGdevices being installed and connected mainly to the LV distributionnetworks that were not initially designed, or even anticipated, for therecent DEG evolution coupled with the increasing addition of complexloads, changing loads and power factors across the distributionnetworks.

In accordance to one aspect, the present invention transforms thetightly legislated and regulated legacy “electrical grid” into a sort of“open-source energy grid” with wide tolerance. In this “open-source”energy grid, an individual energy processing unity (EPU) device isinstalled at each end consumer's POU. These EPU devices are specificallydesigned to tolerant very wide ranges of voltage, current, and frequencyvariation—“dirty power” on the input, and processes the input “dirtypower” to produce high quality “clear power” at the output delivereddirectly at the POU.

The EPU can be simply installed at each POU without any changes to theLV distribution networks, with no limit of the quality and number of DEGdevices that can be installed and connected, hence the present inventionallows the recent evolution to the “electric grid” to evolve to an“open-source energy grid” with the EPU processing the “dirty power” togenerate “clear power” directly at the POU.

For example, in one configuration in accordance to one embodiment of thepresent invention, the input to the EPU can be designed to acceptvoltage tolerance of +−25%, and deliver a voltage with an automaticvoltage regulation (AVR) incorporated in the EPU, at its output, at POUof +−2%. Therefore, for example, the LV distribution network voltagetolerance can be relaxed to +−25%, transmission grid to +−10%, and alsothe DEG devices output Voltage to meet +−10%. So, with the EPU'sinstalled, and the power quality tolerances widened to allow fordistribution network and grid power quality volatility, and the EPU'sdelivering high power quality at POU, the DEG revolution can continuewith increased distribution and network stability and high level ofpower quality at POU, without limiting the numbers of DEG devices thatcan be connected to the LV distribution network.

Also with an EPU installed at the POU, and with the potential powerquality problems of the increased volatility and stability of thedistribution networks with the connection of increasing numbers ofprivately owned and operated domestic and commercial DEG devices, andwith the POU correcting all or some of these tight legacy tolerances,regardless of the wide power quality aberrations on the LV distributionnetwork, especially voltage, PF, harmonics, and current unbalances,there are, in addition, additional advantages in significant energysavings as the output high power quality of the EPU at the POU aretightly controlled, hence significant power savings are also possible.

In another configuration in accordance to one embodiment of the presentinvention, since with the series voltage method, the output voltage ofthe EPU is regulated and held to tight nominal voltage and toleranceregardless and independent of the high distribution voltages at theinput of the EPU, and also since the EPU is bidirectional, any excessenergy connected to the output of the EPU is passed back to its inputand onto the HV distribution network, regardless of the high voltages onthe distribution network. However, when the DEG interface is connectedto the EPU output, the DEG interface control electronics only sees andsenses the normal and nominal regulated EPU output, hence the DEGinterface electronics will continue to operate normally with full energyrecovery. As such, the EPU of the present invention solves the problemassociated with the increasing number of DEG installations on the LVdistribution networks.

FIG. 4 shows the DEG 402 connection to the output of the EPU 401, whichis also connected to the actual premises POU. Since the EPU 401 operatesas a series voltage regulator, basically “isolating” the DEG interfacefrom the high distribution voltages, the DEG interface and energyrecovery operates normally as the DEG control electronics only sees orsenses the fixed and set nominal EPU regulated output voltage, and anyexcess DEG energy is passed back through the bidirectional EPU to theEPU input connected to the distribution network regardless of the highvoltages on the distribution network, allowing normal FIT for the user.

In another configuration in accordance to a preferred embodiment of thepresent invention, instead of a full AVR incorporated in the EPU, theEPU can be designed for maximum energy savings utilizing conservativevoltage reduction (CVR), so the EPU can be configured with only avoltage decreasing AC voltage regulator in conjunction with a seriesbypass contactor for lower cost and additional energy savings under thecondition of low voltage AC mains. So instead of the EPU utilizing afull AVR that will boost the voltage up to the set regulated outputvoltage but will lose the additional energy savings if just an EPU witha voltage decreasing AC voltage regulator is used in conjunction with aseries bypass contactor. For example in this energy saving optimizationconfiguration of the EPU, the present invention is related to optimizingenergy savings of the EPU and also protecting the electrical loads fromovervoltages and energy wasting high AC input voltages above an optimumenergy savings level. In the case of the input mains AC voltage fallingbelow a selected optimum level, as if a full AVR is utilized in the EPU,the full AVR not only continues to use its internal power electronics toboost the low input AC voltage to the set regulated output AC voltage,the AVR would increase or boost the input AC mains voltage to the setoptimum output energy savings voltage level, then the energy savingswould not be optimized under low input mains AC voltage, as the inputcurrent hence the input power would increase as the full AVR increasesor boosts the low mains input AC Voltage.

In this preferred embodiment of the present invention, if the input ACmains voltage drops below the optimum energy savings voltage or a lowerselected voltage point, the voltage decreasing power electronics in theEPU are switched out to save the voltage decreasing AC voltage regulatorinternal power electronics usage, and the series bypass contactor isactivated, so that the lower mains voltage is directly delivered to theelectrical load, hence achieving even more energy savings than in thecase if a full voltage increasing AVR is used in an alternate EPUconfiguration. The principles of the present invention are readilyapplicable to any poly-phase AC system, such as a single or 3-phaseelectrical system.

For example in worldwide electrical systems, the final LV distributionvoltages are generally either 110/120 VAC systems, or 220/230/240 VACsystems, although most of the world is standardizing to nominal 120 VACor 230 VAC systems for LV distribution voltages. Also there arestandardized and legislated electrical system specifications, andespecially distribution voltage levels and tolerances to be delivered tothe switchboards of domestic and commercial premises. For example in theUnited States the standard distribution voltage for domestic andcommercial premises is 120 VAC (specified by FERC/NERC), and voltagetolerances of maximum of +5%, and minimum of −5%. In the higher voltage230 VAC systems such as Australia (specified by AS60038), and the UK(Specified by EN50160), the allowed voltages tolerances are specified asa maximum of +10%, and a minimum of −6%. Although it is accepted in theindustry that overvoltage levels can be higher, and an overvoltage of+10%, and an undervoltage of −10% as extreme limits, but stillacceptable. But these extreme and maximum voltages when applied toelectronic equipment and appliances, especially electrical motors, thatare designed to the nominal specified standard voltages such as 120 VACin the United States and 230 VAC in Australia and UK, not only wasteenergy because of the additional higher working voltage, but also do notperform optimally, motors and transformers can overheat, shorten workinglife times, and can permanently damage any equipment connected to theelectrical system.

So, say for the United States, the voltage range, from a nominal 120VAC, for a maximum voltage of +5% is 126 VAC, and a +10% overvoltagelevel of 132 VAC, and a minimum of −5% is 114 VAC, with an undervoltageof −10% of 108 VAC. It is generally accepted in the industry that thetransmission and distribution operators in the United States willdeliver the minimum voltage of 114 VAC to the premises switchboard, andallowing another 3.5% voltage drop estimated for a minimum of 110 VAC tothe actual loads, such as appliances in domestic premises.

To deliver the specified range of voltages within the allowed voltagetolerances from the nominal voltage of 120 VAC to say each domestic orcommercial premises on a local power island distribution network, itrequires a higher voltage at the input to the local power islanddistribution network, because of the voltage drop that takes placeserially along the physical wires of the distribution network due to theelectrical resistance of the wires and system conductors. So typicallypremises close to the sub-station of the distribution network localpower island will see the higher maximum voltage ranges, and furtheralong the local power island distribution network, the lower voltages inthe range. So for the United States, the voltage range can be from 126VAC or even higher, down to 114 VAC or even lower, for a nominal 120 VAClocal power island distribution network.

Similarly for the nominal 230 VAC countries, such as Australia and theUK, the voltage range can be from 253 VAC or even higher at the localpower island substation, down to 216 VAC or even lower along thedistribution network, for a nominal 230 VAC local power islanddistribution network.

So there have been major investments made into the local power islanddistribution networks to minimize the tolerances of the delivered mainsAC voltage to all domestic and commercial premises, but this has becomemore difficult due to the increasing usage and complex electronic loadsbeing added into domestic and commercial premises coupled with changingloads and power factors. In the United States for example, there is nowmore electrical power being used by domestic and commercial premisesthat industrial usage. With the aforesaid problems associated with DEG,the problems compound dramatically in terms of power system complexity,voltage range volatility, and especially overvoltages.

Electrical and electronic equipment and appliances, especiallyelectrical motors, are specifically design to operate at the nominalspecified standard voltages, such as 120 VAC in the United States, andother 120 VAC countries, and 230 VAC in Australia, UK, and other 230 VACcountries. Voltage over the nominal design standard voltage not only candamage the connected electrical and electronic equipment, but they alsoconsume more energy than is necessary, motors and transformers canoverheat, hence there is an optimum voltage in general that optimizesthe performance and delivers the maximum energy savings. So for example,in an EPU optimized for maximum energy savings utilizing CVR, theoptimum energy savings voltage is selected to be the nominal mainsvoltage −5% to achieve normal equipment performance, and maximize energysavings. So that energy savings set voltage could be 114 VAC for nominal120 VAC systems, and 220 VAC for nominal 230 VAC systems, or other lowerenergy saving voltages could be selected, and this is just an example toclearly show the concept.

Therefore, in this preferred embodiment of the present invention, only avoltage decreasing AC voltage regulator is needed working in conjunctionwith a series bypass contactor, and the output voltage of the voltagedecreasing AC voltage regulator is set at energy saving level of 114 VACfor nominal 120 VAC systems, and set at energy saving level of 220 VACfor 230 VAC systems, so under the conditions of extreme or overvoltagesthe voltage decreasing AC voltage regulator keeps the output voltage tothe load at the selected set energy savings voltages. Under theconditions of the input AC mains voltage falling below the energysavings set voltage (in this example 114 VAC for nominal 120 VACsystems, and 220 VAC for nominal 230 VAC systems), if a full AVR isused, then the full AVR will not only be using internal power toincrease or boost the low input mains AC voltage, but that will not saveas much energy as the present invention, as below the set energy savingvoltage, the control electronics will sense the low input AC mainsvoltage, switch off the voltage decreasing AC voltage regulator powerelectronics saving internal energy, and activate the series bypasscontactor, hence the low main AC input voltage is now applied directlyto the load, minimizing the voltage drop if the voltage decreasing ACvoltage regulator stayed connected in the circuit, and additional energysavings is achieved by this low input mains AC voltage being applieddirectly to the load through the series bypass contactor. Also when theinput mains AC voltage increases above the set energy savings voltage,the series bypass contactor is switched out, and the voltage decreasingAC voltage regulator is activated to regulate the output AC voltage tothe load at the energy savings voltage level, regardless of the higherand extreme overvoltages on the distribution network.

In another embodiment of the present invention, a specific energysavings EPU with just the voltage decreasing AC voltage regulatorworking in conjunction with a series bypass contactor incorporatesstandard digital communications as designed in many “smart meters”. Thisway, the energy savings EPU utilizing CVR could be called an “energysaving meter” as it not only performs and reports as a “smart meter” incommunicating over the various standard modes of “smart meter” digitalcommunication, but it also can save energy.

To illustrate the decreasing of the EPU output voltage to an optimumenergy savings level, in the example say 114 VAC for a 120 VAC system,and say 220 VAC for a 230 VAC or 240 VAC system, savings of 10% to 15%can be achieved, and these savings will be increased under low voltageconditions below the 114 VAC in the 120 VAC system, or 220 VAC in the230 VAC or 240 VAC systems in this lower cost energy savings EPU usingjust a voltage decreasing AC voltage regulator in conjunction with aseries bypass contactor, instead of an EPU utilizing a full AVR.

The EPU can be designed to work in a bi-directional digitalcommunication network, which can be used to communicate to a centrallocation the status of the EPU devices and the LV distribution network.This transmitted data can be used to modify the operation of the EPUdevices to alleviate LV distribution network problems, and also the EPUpower island can be isolated to operate as a “micro grid” (403 in FIG.4), in that local power area, and because of the relaxed power qualitytolerances on the LV distribution network, the LV distribution networkor micro grid can operate with much wider power quality volatility,while the EPU's process that “dirty power” to deliver “clean power” atthe POU. Also the digital data can be used on much wider power islandareas, to modify the overall interaction and operation of thegenerators, transmission grid, DEG's, and EPU's to maintain thestability of the power system, but with the wider power qualitytolerances on the Power System, because of the installation of EPU's, itallows much easier overall system control with increased distributionpower quality volatility, while the EPU's still deliver high powerquality “clean power” at the POU.

There are two ways to regulate voltage on the AC mains. One is by seriesvoltage regulation, where the AC input and AC output are “decoupled”with only the differential voltage between the unregulated input ACvoltage and the specified and fixed regulated output AC voltage beingprocessed by the power electronics. The other method is by shunt currentregulation, where the AC voltage is changed by injecting a specifiedcurrent in shunt or parallel with the mains, and adjusting the level ofthe specified current being injected or absorbed by the powerelectronics interfacing with an internal storage device, such as a highvoltage electrolytic capacitor. The shunt current regulation method,therefore, controls the AC mains line voltage by driving or absorbing aspecified current interfacing with an internal storage device across themains line impedance or resistance.

The EPU voltage regulation in accordance to the embodiments of thepresent invention is by series voltage regulation methods including, butnot limited to, the series AC high frequency voltage regulatortechniques disclosed in U.S. Provisional Utility Patent Application No.61/913,935, U.S. Provisional Utility Patent Application No. 61/913,934,and U.S. Provisional Utility Patent Application No. 61/908,763. Theseries voltage regulation methods have major advantages over the shuntcurrent regulation method. The shunt current regulation method requiressignificant current to be generated to change the voltage differentialunder the conditions where the AC line impedance is very low. The ACline impedance is typically much less than 1 ohm, and in many cases canbe less than 0.1 ohm, and is also changing depending on line conditions.Thus, the shunt current regulation method is inefficient and limited inits ability to drive sufficient current into the low line impedances toregulate the voltage over a wide range, and in some cases, with a verylow line impedance cannot generate or absorb sufficient current tocorrect to the required voltage. The series voltage regulation method,as used in the present invention, is highly efficient, does not need aninternal storage device such as an unreliable high voltage electrolyticcapacitor necessary for the shunt configuration, and can regulate the ACoutput voltage over a very wide range of input AC voltages, isindependent of line impedances, and can be operated independently as astandalone AC series voltage regulation AVR.

FIG. 5 shows the configuration of an EPU in accordance to one embodimentof the present invention and the following table lists its operatingparameters in addressing the aforesaid power qualify problems.

Output to Power Quality Problems Input to EPU POU Notes 1) Rapid voltagechange V up to ± 25% V ± 2% Fast electronic control eliminates rapidvoltage changes 2) Low frequency voltage V up to ± 25% V ± 2% Eliminateslow change frequency voltage changes 3) Under voltage dips V drop to−25% V ± 2% Eliminates under voltage dips 4) Over voltage surges V up to+25% V ± 2% Eliminates voltage surges 5) Over voltage spikes and V up to± 25% V ± 2% Eliminates over voltage noise Noise protected spikes andnoise 6) Voltage unbalance V/phase ± 10% V/phase ± Balance voltage 2%unbalance 7) Voltage harmonics THD up to ± THD ± 3% Elements majorvoltage 10% harmonic 8) Power factor PF ≧ 0.98 PF ≧ 0.5 Load PFcorrected at load PF input 9) Current unbalance I/phase ± 10% I/phase ±Load current unbalance 2% corrected at input 10) Frequency deviation F ±5% F ± 1% Frequency derivation corrected 11) DEG grid interfacedistribution Fixed EPU output voltage is control electronics networknominal regulated so the DEG shutoff eliminating regulated gridinterface operates DEG energy recovery voltage normally and excess andFIT for the user DEG energy flows bidirectionally back to thedistribution network

The foregoing description of the present invention has been provided forthe purposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise forms disclosed.Many modifications and variations will be apparent to the practitionerskilled in the art.

The embodiments were chosen and described in order to best explain theprinciples of the invention and its practical application, therebyenabling others skilled in the art to understand the invention forvarious embodiments and with various modifications that are suited tothe particular use contemplated. It is intended that the scope of theinvention be defined by the following claims and their equivalence.

What is claimed is:
 1. An electrical power distribution system with distributed energy generation, comprising: an electrical power distribution network; one or more energy processing units each being installed directly at one of one or more points of use; wherein each of the energy processing units having an input connection connected to the electrical power distribution network and an output connection connected to one or more of loads and distributed energy generation devices in the point of use at which the energy processing unit is installed; wherein each of the energy processing units generates a regulated output voltage at its output from an unregulated input voltage in the electrical power distribution network at the energy processing unit input; wherein each of the energy processing units comprises a series voltage regulator and generates its regulated output voltage using a series voltage regulation method combined with at least one of one or more power quality functions; wherein each of the energy processing units being electrical bidirectional allowing energy recovery of excess energy generated by any distributed energy generation device in the point of use at which the energy processing unit is installed to be passed back to the energy processing unit input and onto the electrical power distribution network; and wherein the regulated output voltage at the output connection of the energy processing unit allowing continuous energy recovery when the unregulated input voltage in the electrical power distribution network is above a regulated upper limit.
 2. The system of claim 1, wherein the one or more power quality functions include power factor control, load balancing, voltage balancing, harmonic correction, and frequency control.
 3. The system of claim 1, wherein the unregulated input voltage in the electrical power distributed network being allowed a tolerance of ±25% from nominal voltage change, ±10% from nominal voltage unbalance, ±10% from nominal voltage harmonics, low power factor corrected to more than 0.98, ±10% from nominal current unbalance, ±5% from nominal frequency deviation.
 4. The system of claim 1, wherein the unregulated input voltage in the electrical power distributed network being allowed a tolerance higher than a legislated electrical power quality standard tolerance.
 5. The system of claim 1, wherein the energy processing units being equipped with bidirectional data communication means for data communication with power generators and power transmission operators in the electrical power distribution network.
 6. The system of claim 1, wherein the series voltage regulator in each of the energy processing units being a series alternate current high frequency voltage regulator defined in U.S. Patent Application No. 61/896,635.
 7. The system of claim 1, wherein the series voltage regulator in each of the energy processing units being a series alternate current high frequency voltage regulator defined in U.S. Patent Application No. 61/896,639.
 8. The system of claim 1, wherein the series voltage regulator in each of the energy processing units being a series alternate current high frequency voltage regulator defined in U.S. Patent Application No. 61/908,763.
 9. The system of claim 1, wherein the series voltage regulator in each of the energy processing units being a series alternate current high frequency voltage regulator defined in U.S. Patent Application No. 61/913,934.
 10. The system of claim 1, wherein the series voltage regulator in each of the energy processing units being a series alternate current high frequency voltage regulator defined in U.S. Patent Application No. 61/913,935.
 11. The system of claim 1, wherein each of the energy processing units further comprises a series bypass contactor and achieves energy saving using a conservative voltage reduction method; wherein the conservative voltage reduction method comprises: passing the unregulated input voltage through the series voltage regulator when the unregulated input voltage is above the regulated upper limit; and passing the unregulated input voltage through the series bypass contactor when the unregulated input voltage is below the regulated upper limit.
 12. The system of claim 11, wherein the series voltage regulator in each of the energy processing units being a series alternate current high frequency voltage regulator defined in U.S. Patent Application No. 61/896,635.
 13. The system of claim 11, wherein the series voltage regulator in each of the energy processing units being a series alternate current high frequency voltage regulator defined in U.S. Patent Application No. 61/896,639.
 14. The system of claim 11, wherein the series voltage regulator in each of the energy processing units being a series alternate current high frequency voltage regulator defined in U.S. Patent Application No. 61/908,763.
 15. The system of claim 11, wherein the series voltage regulator in each of the energy processing units being a series alternate current high frequency voltage regulator defined in U.S. Patent Application No. 61/913,934.
 16. The system of claim 11, wherein the series voltage regulator in each of the energy processing units being a series alternate current high frequency voltage regulator defined in U.S. Patent Application No. 61/913,935. 